30 results on '"Escalle, Lauriane"'
Search Results
2. Biodegradable drifting fish aggregating devices: Current status and future prospects
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Zudaire, Iker, Moreno, Gala, Murua, Jefferson, Hamer, Paul, Murua, Hilario, T. Tolotti, Mariana, Roman, Marlon, Hall, Martin, Lopez, Jon, Grande, Maitane, Merino, Gorka, Escalle, Lauriane, C. Basurko, Oihane, Capello, Manuela, Dagorn, Laurent, Ramos, Maria Lourdes, Abascal, Francisco J., Báez, José Carlos, Pascual-Alayón, Pedro J., Déniz, Santiago, and Santiago, Josu
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- 2023
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3. Towards non-entangling and biodegradable drifting fish aggregating devices – Baselines and transition in the world’s largest tuna purse seine fishery
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Escalle, Lauriane, Mourot, Jennyfer, Hamer, Paul, Hare, Steven R., Phillip, Naiten Bradley, Jr., and Pilling, Graham M.
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- 2023
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4. Assessing the drift of fish aggregating devices in the tropical Pacific Ocean
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Sub Physical Oceanography, Marine and Atmospheric Research, Frankemölle, Philippe F.V.W., Nooteboom, Peter D., Scutt Phillips, Joe, Escalle, Lauriane, Nicol, Simon, Van Sebille, Erik, Sub Physical Oceanography, Marine and Atmospheric Research, Frankemölle, Philippe F.V.W., Nooteboom, Peter D., Scutt Phillips, Joe, Escalle, Lauriane, Nicol, Simon, and Van Sebille, Erik
- Published
- 2024
5. Simulating drifting fish aggregating device trajectories to identify potential interactions with endangered sea turtles.
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Escalle, Lauriane, Scutt Phillips, J., Lopez, J., Lynch, J. M., Murua, H., Royer, S. J., Swimmer, Y., Murua, J., Sen Gupta, Alex, Restrepo, V., and Moreno, G.
- Abstract
Purse‐seine fishers using drifting fish aggregating devices (dFADs), mainly built with bamboo, plastic buoys, and plastic netting, to aggregate and catch tropical tuna, deploy 46,000–65,000 dFADs per year in the Pacific Ocean. Some of the major concerns associated with this widespread fishing device are potential entanglement of sea turtles and other marine fauna in dFAD netting; marine debris and pollution; and potential ecological damage via stranding on coral reefs, beaches, and other essential habitats for marine fauna. To assess and quantify the potential connectivity (number of dFADs deployed in an area and arriving in another area) between dFAD deployment areas and important oceanic or coastal habitat of critically endangered leatherback (
Dermochelys coriacea ) and hawksbill (Eretmochelys imbricata ) sea turtles in the Pacific Ocean, we conducted passive‐drift Lagrangian experiments with simulated dFAD drift profiles and compared them with known important sea turtle areas. Up to 60% of dFADs from equatorial areas were arriving in essential sea turtle habitats. Connectivity was less when only areas where dFADs are currently deployed were used. Our simulations identified potential regions of dFAD interactions with migration and feeding habitats of the east Pacific leatherback turtle in the tropical southeastern Pacific Ocean; coastal habitats of leatherback and hawksbill in the western Pacific (e.g., archipelagic zones of Indonesia, Papua New Guinea, and Solomon Islands); and foraging habitat of leatherback in a large equatorial area south of Hawaii. Additional research is needed to estimate entanglements of sea turtles with dFADs at sea and to quantify the likely changes in connectivity and distribution of dFADs under new management measures, such as use of alternative nonentangling dFAD designs that biodegrade, or changes in deployment strategies, such as shifting locations. [ABSTRACT FROM AUTHOR]- Published
- 2024
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6. Assessing the drift of fish aggregating devices in the tropical Pacific Ocean
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Frankemölle, Philippe F. V. W., primary, Nooteboom, Peter D., additional, Scutt Phillips, Joe, additional, Escalle, Lauriane, additional, Nicol, Simon, additional, and van Sebille, Erik, additional
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- 2024
- Full Text
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7. Catch and bycatch captured by tropical tuna purse-seine fishery in whale and whale shark associated sets: comparison with free school and FAD sets
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Escalle, Lauriane, Gaertner, Daniel, Chavance, Pierre, Murua, Hilario, Simier, Monique, Pascual-Alayón, Pedro Jose, Ménard, Frédéric, Ruiz, Jon, Abascal, Francisco, and Mérigot, Bastien
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- 2019
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8. Benefits, concerns, and solutions of fishing for tunas with drifting fish aggregation devices
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Pons, Maite, primary, Kaplan, David, additional, Moreno, Gala, additional, Escalle, Lauriane, additional, Abascal, Francisco, additional, Hall, Martin, additional, Restrepo, Victor, additional, and Hilborn, Ray, additional
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- 2023
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9. Assessing the drift of Fish Aggregating Devices in the tropical Pacific Ocean
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Frankemölle, Philippe Friederickus Vincentius Wenceslaus, primary, Nooteboom, Peter Dirk, additional, Scutt Phillips, Joe, additional, Escalle, Lauriane, additional, Nicol, Simon, additional, and van Sebille, Erik, additional
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- 2023
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10. Benefits, concerns, and solutions of fishing for tunas with drifting fish aggregation devices
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Pons, Maite, Kaplan, David, Moreno, Gala, Escalle, Lauriane, Abascal, Francisco, Hall, Martin, Restrepo, Victor, Hilborn, Ray, Pons, Maite, Kaplan, David, Moreno, Gala, Escalle, Lauriane, Abascal, Francisco, Hall, Martin, Restrepo, Victor, and Hilborn, Ray
- Abstract
Drifting fish aggregating devices (dFADs) are human-made floating objects widely used by tropical tuna purse seine (PS) fisheries to increase catch of target species. However, dFAD use has several negative impacts, including increased potential for overfishing, higher juvenile tuna catch, higher bycatch compared to other PS fishing modes, ghost-fishing, and generation of marine litter. Based on these impacts, some stakeholders, especially environmental non-governmental organizations and other competing fishing industries, suggest that dFADs should be completely banned. We list the pros and cons of dFAD fishing; address how to improve current management; and suggest solutions for the sustainability of dFAD fishing in the long term. A dFAD ban would lead to major changes in the availability and sourcing of tuna for human consumption and decrease the licensing revenue received by many developing states. Most importantly, we argue that tools exist today to manage for, reduce or eliminate most of the negative impacts of dFADs (e.g., bans on discards, limits on active dFADs, biodegradable non-entangling constructions, time-area deployment closures, recovery programs, and full data transparency, among others). Management decisions based on sound scientific reasoning are needed to address the legitimate concerns surrounding dFAD use and ensure the sustainability of both pelagic and coastal ecosystems and tropical tuna PS fisheries.
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- 2023
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11. Benefits, concerns, and solutions of fishing for tunas with drifting fish aggregation devices
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Abascal, Francisco Javier [0000-0002-8550-8617], Pons, Maite, Kaplan, David, Moreno, Gala, Escalle, Lauriane, Abascal, Francisco Javier, Hall, Martin, Restrepo, Victor, Hilborn, Ray, Abascal, Francisco Javier [0000-0002-8550-8617], Pons, Maite, Kaplan, David, Moreno, Gala, Escalle, Lauriane, Abascal, Francisco Javier, Hall, Martin, Restrepo, Victor, and Hilborn, Ray
- Abstract
Drifting fish aggregating devices (dFADs) are human-made floating objects widely used by tropical tuna purse seine (PS) fisheries to increase catch of target species. However, dFAD use has several negative impacts, including increased potential for overfishing, higher juvenile tuna catch, higher bycatch compared to other PS fishing modes, ghost-fishing, and generation of marine litter. Based on these impacts, some stakeholders, especially environmental non-governmental organizations and other competing fishing industries, suggest that dFADs should be completely banned. We list the pros and cons of dFAD fishing; address how to improve current management; and suggest solutions for the sustainability of dFAD fishing in the long term. A dFAD ban would lead to major changes in the availability and sourcing of tuna for human consumption and decrease the licensing revenue received by many developing states. Most importantly, we argue that tools exist today to manage for, reduce or eliminate most of the negative impacts of dFADs (e.g., bans on discards, limits on active dFADs, biodegradable non-entangling constructions, time-area deployment closures, recovery programs, and full data transparency, among others). Management decisions based on sound scientific reasoning are needed to address the legitimate concerns surrounding dFAD use and ensure the sustainability of both pelagic and coastal ecosystems and tropical tuna PS fisheries.
- Published
- 2023
12. Biodegradable drifting fish aggregating devices: Current status and future prospects
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Abascal, Francisco Javier [0000-0002-8550-8617], Báez, José Carlos [0000-0003-2049-0409], Pascual-Alayón, Pedro José [0000-0001-9834-4693], Deniz, Santiago [0000-0002-9431-4785], Zudaire, Iker, Moreno, Gala, Murua, Jefferson, Hamer, Paul, Murua, Hilario, T. Tolotti, Mariana, Roman, Marlon, Hall, Martin, Lopez, Jon, Grande, Maitane, Merino, Gorka, Escalle, Lauriane, C. Basurko, Oihane, Capello, Manuela, Dagorn, Laurent, Ramos, María Lourdes, Abascal, Francisco Javier, Báez, José Carlos, Pascual-Alayón, Pedro José, Deniz, Santiago, Santiago, Josu, Abascal, Francisco Javier [0000-0002-8550-8617], Báez, José Carlos [0000-0003-2049-0409], Pascual-Alayón, Pedro José [0000-0001-9834-4693], Deniz, Santiago [0000-0002-9431-4785], Zudaire, Iker, Moreno, Gala, Murua, Jefferson, Hamer, Paul, Murua, Hilario, T. Tolotti, Mariana, Roman, Marlon, Hall, Martin, Lopez, Jon, Grande, Maitane, Merino, Gorka, Escalle, Lauriane, C. Basurko, Oihane, Capello, Manuela, Dagorn, Laurent, Ramos, María Lourdes, Abascal, Francisco Javier, Báez, José Carlos, Pascual-Alayón, Pedro José, Deniz, Santiago, and Santiago, Josu
- Abstract
The structure, materials and designs of drifting Fish Aggregating Devices (dFADs) have generally remained rudimentary and relatively unchanged since they first came into use in the 1980 s. However, more recently, dFADs have been increasing in dimensions and the prevailing use of plastic components. Abandoned, lost or discarded dFADs can therefore contribute to the global marine litter problem. Transitioning to biodegradable and non-toxic materials that have a faster rate of decomposition, and are free of toxins and heavy metals, relative to synthetic materials, has been prescribed as an important part of the solution to reducing marine pollution from industrial tuna fisheries that rely on dFADs. This review of the current state of dFADs considers aspects related to the use of biodegradable materials in their construction, including; regulations related to dFAD materials, trials of biodegradable designs and materials and future alternatives. During the last decade, regulatory measures at tuna Regional Fishery Management Organizations (tRFMOs) have gradually moved towards the clear recommendation to use biodegradable materials in dFAD construction together with other measures limiting the number of active dFADs and the use of netting materials. However, to provide operational guidance, more clarity is needed, starting with a standardised definition of biodegradable dFADs among tRFMOs. Research involving dFAD natural and synthetic materials is required, along with improved data collection for monitoring the transition of dFAD materials against specified standards for biodegradable dFADs. In addition, alternative and complementary actions need to be explored to contribute to minimising adverse effects of dFADs on the environment. Acknowledging the current difficulties for the implementation of fully biodegradable dFADs in tuna fisheries, a stepwise process towards the implementation of commercially viable biodegradable dFADs should be considered.
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- 2023
13. Environmental versus operational drivers of drifting FAD beaching in the Western and Central Pacific Ocean
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Escalle, Lauriane, Scutt Phillips, Joe, Brownjohn, Maurice, Brouwer, Stephen, Sen Gupta, Alex, Van Sebille, Erik, Hampton, John, and Pilling, Graham
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- 2019
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14. Large Floating Abandoned, Lost or Discarded Fishing Gear (Aldfg) is Frequent Marine Pollution in the Hawaiian Islands and Palmyra Atoll
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Royer, Sarah-Jeanne, primary, Corniuk, Raquel, additional, McWhirter, Andrew, additional, Lynch, Harry, additional, Pollock, Kydd, additional, O'Brien, Kevin, additional, Escalle, Lauriane, additional, Stevens, Katherine, additional, Moreno, Gala, additional, and Lynch, Jennifer, additional
- Published
- 2023
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15. Cetaceans and tuna purse seine fisheries in the Atlantic and Indian Oceans : interactions but few mortalities
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Escalle, Lauriane, Capietto, Anna, Chavance, Pierre, Dubroca, Laurent, De Molina, Alicia Delgado, Murua, Hilario, Gaertner, Daniel, Romanov, Evgeny, Spitz, Jérôme, Kiszka, Jeremy J., Floch, Laurent, Damiano, Alain, and Merigot, Bastien
- Published
- 2015
16. Consequences of fishing moratoria on catch and bycatch: the case of tropical tuna purse-seiners and whale and whale shark associated sets
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Escalle, Lauriane, Gaertner, Daniel, Chavance, Pierre, Delgado de Molina, Alicia, Ariz, Javier, and Merigot, Bastien
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- 2016
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17. Assessing the drift of Fish Aggregating Devices in the tropical Pacific Ocean.
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Frankemölle, Philippe F. V. W., Nooteboom, Peter D., Phillips, Joe Scutt, Escalle, Lauriane, Nicol, Simon, and van Sebille, Erik
- Subjects
OCEAN ,ADVECTION ,PEARSON correlation (Statistics) ,FLOW simulations ,PARTICLE tracks (Nuclear physics) ,SOUTHERN oscillation ,TUNA fisheries ,FISHERIES - Abstract
The Tropical Pacific Ocean is characterized by its dominant zonal flow, strong climate dependence on the El Niño Southern Oscillation (ENSO) and abundant tuna stocks. Tuna fisheries in the West and Central Pacific Ocean accounted for 55% of world-wide tuna catch in 2019 and are one of the main sources of income in many Pacific island nations. One of the dominant fishing methods in this region relies on the use of drifting Fish Aggregating Devices (dFADs): rafts with long underwater appendages (on average 50m deep) that attract and aggregate fish. Although currents such as the North Equatorial Countercurrent (NECC) and South Equatorial Current (SEC) in the tropical Pacific Ocean vary strongly with ENSO, little is known about the impact of this variability in flow on dFAD dispersion. In this study, virtual Lagrangian particles are tracked for the period 2006 to 2021 over the domain in a 3D hydrodynamic model and are advected in simulations with only surface flow as well as simulations using a depth-averaged horizontal flow over the upper 50 meters. The particle trajectories are used to determine zonal displacements, eddy-like behaviour and ENSO variability for drifters that are subjected to either surface or depth-averaged currents. It was found that virtual particles that are advected by only surface flow are displaced up to 35% farther than those subjected to a depth-averaged flow, but no other major differences are found in dispersion patterns. Strongest correlations between ENSO and dFAD dispersion for the assessed variables were found in the West Pacific Ocean, with Pearson correlation coefficients up to 0.59 for dFAD displacement. Connections between ENSO and eddy-like behaviour were found in the western part of the SEC, indicating more circulation and meandering during el Niño. These findings may be useful for improving sustainable deployment strategies during ENSO events, and understanding the ocean processes driving the distribution of dFADs. [ABSTRACT FROM AUTHOR]
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- 2023
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18. Assessing the drift of Fish Aggregating Devices in the tropical Pacific Ocean.
- Author
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Frankemölle, Philippe Friederickus Vincentius Wenceslaus, Nooteboom, Peter Dirk, Phillips, Joe Scutt, Escalle, Lauriane, Nicol, Simon, and Sebille, Erik van
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OCEAN ,ADVECTION ,PEARSON correlation (Statistics) ,FLOW simulations ,PARTICLE tracks (Nuclear physics) ,SOUTHERN oscillation ,TUNA fisheries ,FISHERIES - Abstract
The Tropical Pacific Ocean is characterized by its dominant zonal flow, strong climate dependence on the El Niño Southern Oscillation (ENSO) and abundant tuna stocks. Tuna fisheries in the West and Central Pacific Ocean accounted for 55 % of world-wide tuna catch in 2019 and are one of the main sources of income in many Pacific island nations. One of the dominant fishing methods in this region relies on the use of drifting Fish Aggregating Devices (dFADs): rafts with long underwater appendages (on average 50 m deep) that attract and aggregate fish. Although currents such as the North Equatorial Countercurrent (NECC) and South Equatorial Current (SEC) in the tropical Pacific Ocean vary strongly with ENSO, little is known about the impact of this variability in flow on dFAD dispersion. In this study, virtual Lagrangian particles are tracked for the period 2006 to 2021 over the domain in a 3D hydrodynamic model and are advected in simulations with only surface flow as well as simulations using a depth-averaged horizontal flow over the upper 50 meters. The particle trajectories are used to determine zonal displacements, eddy-like behaviour and ENSO variability for drifters that are subjected to either surface or depth-averaged currents. It was found that virtual particles that are advected by only surface flow are displaced up to 35 % farther than those subjected to a depth-averaged flow, but no other major differences are found in dispersion patterns. Strongest correlations between ENSO and dFAD dispersion for the assessed variables were found in the West Pacific Ocean, with Pearson correlation coefficients up to 0.59 for dFAD displacement. Connections between ENSO and eddy-like behaviour were found in the western part of the SEC, indicating more circulation and meandering during el Niño. These findings may be useful for improving sustainable deployment strategies during ENSO events, and understanding the ocean processes driving the distribution of dFADs. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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19. Quantifying drifting Fish Aggregating Device use by the world's largest tuna fishery
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Escalle, Lauriane, primary, Hare, Steven R, additional, Vidal, Tiffany, additional, Brownjohn, Maurice, additional, Hamer, Paul, additional, and Pilling, Graham, additional
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- 2021
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20. Elasmobranch bycatch distributions and mortality: insights from the European tropical tuna purse-seine fishery
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Clavareau, Lyndsay, Sabarros, Philippe, Escalle, Lauriane, Bach, Pascal, Abascal, Francisco J., Lopez, Jon, Murua, Hilario, Pascual Alayon, Pedro J., Ramos, Maria Lourdes, Ruiz, Jon, Mérigot, Bastien, Clavareau, Lyndsay, Sabarros, Philippe, Escalle, Lauriane, Bach, Pascal, Abascal, Francisco J., Lopez, Jon, Murua, Hilario, Pascual Alayon, Pedro J., Ramos, Maria Lourdes, Ruiz, Jon, and Mérigot, Bastien
- Abstract
Despite bycatch of elasmobranch (sharks and rays) being a major concern in most fisheries worldwide, there is a lack of knowledge on their spatio-temporal species distribution, biology (life stage and sex-ratios), as well as their at-haulback mortality rate. Observer data from the French and Spanish tropical purse-seine tuna fisheries operating in the Eastern Atlantic and Western Indian Oceans between 2005 and 2017 were analysed to investigate elasmobranch bycatch. Data included 24 elasmobranchs species and distribution patterns of catch per unit of effort (CPUE) by species and sex-ratio were found to vary with life stages, areas, seasons and fishing modes. In general, higher catches were found in FAD-associated sets (>40%) than free tuna school sets (<17%) although this can vary depending on the species. For the large majority of species, a high proportion of juveniles were caught (30.7–100%), apparent at-haulback mortality rates was high (24.3–63.9%) and finally sex ratios was unbalanced (13.3–66.7% of females). Areas and seasons identified from these different components should be of interest for the monitoring and management of elasmobranch bycatches.
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- 2020
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21. Elasmobranch bycatch distributions and mortality: Insights from the European tropical tuna purse-seine fishery
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Clavareau, Lyndsay, primary, Sabarros, Philippe S., additional, Escalle, Lauriane, additional, Bach, Pascal, additional, Abascal, Francisco J., additional, Lopez, Jon, additional, Murua, Hilario, additional, Pascual Alayon, Pedro J., additional, Ramos, Maria Lourdes, additional, Ruiz, Jon, additional, and Mérigot, Bastien, additional
- Published
- 2020
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22. Environmental versus operational drivers of drifting FAD beaching in the Western and Central Pacific Ocean
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Sub Physical Oceanography, Marine and Atmospheric Research, Escalle, Lauriane, Scutt Phillips, Joe, Brownjohn, Maurice, Brouwer, Stephen, Sen Gupta, Alex, Van Sebille, Erik, Hampton, John, Pilling, Graham, Sub Physical Oceanography, Marine and Atmospheric Research, Escalle, Lauriane, Scutt Phillips, Joe, Brownjohn, Maurice, Brouwer, Stephen, Sen Gupta, Alex, Van Sebille, Erik, Hampton, John, and Pilling, Graham
- Published
- 2019
23. Catch and bycatch captured by tropical tuna purse-seine fishery in whale and whale shark associated sets: comparison with free school and FAD sets
- Author
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Escalle, Lauriane, primary, Gaertner, Daniel, additional, Chavance, Pierre, additional, Murua, Hilario, additional, Simier, Monique, additional, Pascual-Alayón, Pedro Jose, additional, Ménard, Frédéric, additional, Ruiz, Jon, additional, Abascal, Francisco, additional, and Mérigot, Bastien, additional
- Published
- 2018
- Full Text
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24. Spatio-temporal interactions between whale sharks, cetaceans and tropical tuna purse-seine fisheries, within a conservation perspective, in the Atlantic and Indian Oceans
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Escalle, Lauriane, MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier, Daniel Gaertner, Bastien Merigot, and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD)
- Subjects
Whale shark ,Cetaceans ,Écosystèmes pélagiques ,Accidental catch ,[SDV.BA]Life Sciences [q-bio]/Animal biology ,Pêche thonière à la senne ,Megafaune marine ,Tuna purse-Seine fishery ,Requin baleine ,Marine magafauna ,Prises accessoires ,Cétacés ,Pelagic ecosystems - Abstract
In the frame of the Ecosystem Approach to Fishery (EAF) management, impact of the tropical tuna purse-seine fishery on targeted and incidentally captured species should be investigated. They may include megafauna species, such as sharks, rays, cetaceans, turtles or sea birds, which often are emblematic and vulnerable species. Tropical tuna purse-seiners actively search, at the surface of the sea, for clues indicating the presence of tuna schools (e.g. birds, floating objects, whales, dolphins or whale sharks). In the eastern Atlantic and western Indian Oceans, the main two fishing modes are sets on free swimming tuna schools and schools associated to natural or artificial floating objects, thereafter called Fish Aggregating Device (FAD). However dedicated studies on fishing sets associated to whale sharks and cetaceans are still lacking. The aim of this thesis is therefore, using logbook and scientific onboard observer data, to investigate the spatio-temporal co-occurrences and/or interactions between whale sharks, cetaceans and the tuna purse-seine fishery within an ecosystem conservation perspective. This work underlines that the megafauna/ fishery co-occurrence occurs in specific spatio-temporal strata: i) Gabon to Angola (April–September), ii) the Mozambique Channel (June–September), and iii) East of Seychelles (April–September). As baleen whales and whale sharks are filter feeders, the co-occurrence with the purse-seine fishery was mostly linked to highly productive environments (i.e. using proxys including chlorophyll-a concentration). In addition fishing sets involving megafauna were relatively high before 2000 (up to 20% of the sets), but are nowadays less frequent (AC3 and 1.5% of the sets associated to baleen whales and whale sharks). The purse-seine fishery appears to have a relatively low impact on megafauna species with mortality rates of 1.4% for whale sharks and 5.6% for cetaceans. Whale shark satellite tagging also confirms these results on the longer term, but the low sample size precludes any final conclusion. While dolphins are present in fishing areas, very few interactions with the fishery was detected, which highlights the striking difference with the eastern Pacific Ocean where half the sets are associated to dolphin herds. In addition, the diversity of targeted and bycatch species captured under whale shark and baleen whale sets was also investigated. Whale sharks are principally associated to skipjack and yellowfin (of various sizes) tunas and baleen whales mostly to large yellowfin tuna. In addition, bycatch species associated to these two megafauna groups was relatively low and dominated by the silky shark, and bycatch diversity was close to the one found for free swimming tuna schools. Finally, real and/or simulated encircled megafauna conservation measures or fishing effort management measures (especially FAD moratoria including larger ones) were investigated. The first ones were found to have limited consequences on tuna catch and bycatch. Conversely FAD moratoria had limited impacts on the number of megafauna associated fishing sets, due to the fact that the main spatio-temporal strata of megafauna and FAD sets differ. However larger and longer moratoria could be beneficial for juvenile tuna and some bycatch species. Overall, this thesis has lead to increase the knowledge on megafauna/ fishery interactions, essential in the general framework of setting up an EAF in the tropical tune purse-seine fishery.; Dans le cadre de l’Approche Ecosystémique des Pêches (AEP), il est nécessaire d’évaluer l’impact de la pêche thonière tropicale à la senne sur les espèces ciblées et sur les espèces accessoires. Parmi ces dernières, les espèces de la mégafaune, telles que des requins, raies, cétacés, tortues, oiseaux marins, sont souvent emblématiques et vulnérables. Les thoniers senneurs tropicaux recherchent activement à la surface de l’eau tout indice de la présence de bancs de thon (e.g. oiseaux, objets flottants, baleines, dauphins ou requins baleines). Dans l’est de l’océan Atlantique et l’ouest de l’océan Indien, les deux modes de pêches principaux sont les captures de thons en bancs libres et celles sur bancs associés à un objet flottant, naturel ou artificiel, rassemblés ici sur sous le terme de dispositif de concentration de poisson (DCP). Les calées associées aux requins baleines et aux cétacés sont toutefois peu étudiées. L’objectif de cette thèse est donc d’analyser les co-occurrences et/ou interactions spatio-temporelles entre requins baleines, cétacés et pêche thonière à la senne, dans une perspective de conservation de l’écosystème. Ce travail, basé sur des données de livres de bord et d’observateurs scientifiques embarqués, a montré que la co-occurrence pêche thonière/ mégafaune se localise dans des strates spatio-temporelles relativement précises: i) du Gabon à l’Angola (avril–septembre), ii) dans le Canal du Mozambique (juin–septembre) et iii) à l’est des Seychelles (avril–septembre). Les baleines et requins baleines étant planctivores, la co-occurrence avec la pêche à la senne est principalement liée à une forte productivité primaire (appréhendée à travers des proxys tels que la concentration en chlorophylle-a). De plus, les calées sur ces deux groupes étaient assez élevées avant 2000 (jusqu’à 20% des calées), et qu’elles sont moins fréquentes aujourd’hui (AC3 et 1,5% des calées associées à des baleines et des requins baleines, respectivement). L’impact de la pêche à la senne sur ces espèces semble relativement faible au regard du taux de mortalité apparente de 1,4% pour les requins baleines et 5,6% pour les cétacés. Des marquages satellites réalisés sur les requins baleines, confirment ces observations sur le plus long terme, mais la taille de l’échantillon limite la formulation de conclusions définitives. Concernant les dauphins, bien que présents sur les zones de pêche, ils interagissent très peu avec celle-ci, soulignant ainsi une différence majeure avec l’océan Pacifique est où ce mode de pêche est majoritaire. La diversité spécifique des espèces cible et accessoire associées aux calées sur mégafaune a également été étudiée. Les requins baleines sont associés aux listaos et à l’albacore (dans une large gamme de tailles), alors que les baleines le sont principalement à de gros albacores. De plus, la capture accessoire associée à ces deux groupes de mégafaune est relativement faible et dominée par le requin soyeux et la diversité spécifique est proche de celle trouvée sous les bancs libres de thons. Enfin les effets de mesures de conservation vis-à-vis de la mégafaune encerclée ou de mesures de gestion de l’effort de pêche, notamment les moratoires sur DCP réelles ou simulées (e.g. moratoires élargis), ont été analysés. Les premières ont eu un effet limité en terme de captures cibles et accessoires, alors que les moratoires impactent peu le nombre de calées associés à la mégafaune, ceci en raison du décalage spatio-temporel des co-occurrences. Cependant des moratoires élargis pourraient être bénéfiques pour les thons juvéniles et certaines espèces associées. Par l’analyse quantitative des interactions entre la pêche thonière à la senne et la mégafaune, cette thèse apporte des connaissances essentielles sur les espèces étudiées dans le cadre de la mise en place d’une AEP, applicable à la pêche thonière tropicale.
- Published
- 2016
25. Post-capture survival of whale sharks encircled in tuna purse-seine nets: tagging and safe release methods
- Author
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Escalle, Lauriane, Murua, Hilario, Amande, Justin Monin, Arregui, Igor, Chavance, Pierre, Delgado De Molina, Alicia, Gaertner, Daniel, Fraile, Igaratza, Filmalter, John David, Santiago, Josu, Forget, Fabien, Arrizabalaga, Haritz, Dagorn, Laurent, Merigot, Bastien, MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD), and Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
[SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems ,Rhincodon typus ,mega fauna ,[SDE.MCG]Environmental Sciences/Global Changes ,PSAT ,tropical tuna purse-seine ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,tropical tuna ,purse-seine ,post-release mortality - Abstract
International audience; 1. Whale shark, the world's largest fish, is believed to be particularly vulnerable owing to its biological characteristics (slow growth, late maturation, great longevity) and is listed as Vulnerable by IUCN and included in Appendix II of CITES.2. Whale sharks are occasionally encircled in tropical tuna purse-seine nets, throughout this global fishery. Although apparent immediate survival rates following encirclement and release have recently been assessed through scientific onboard observer programmes, a more rigorous methodology is still required for studying post-released survival.3. This work provides a method for applying pop-up satellite tags and reports an enhanced release procedure for whale sharks. The first assessment of survival after release from purse-seine nets involved six whale sharks tagged between May and September 2014 in the eastern tropical Atlantic Ocean. Five tags transmitted data: three popped up as programmed (after 30 days), while two surfaced prematurely (one after 21 and the other after 71 days (programmed to pop off after 30 and 90 days, respectively)) but showed no sign of unusual behaviour.4. Overall, whale sharks survived at least 21 days (one at least 71 days) after release from purse-seine nets. These observations based on five large individuals (total length > 8 m), suggest that whale sharks have a good chance of survival when released with the proposed method.5. Additional tagging in this and other oceans, especially of juveniles which may be more sensitive to encirclement and release operations, is essential to further assess whale shark post-release survival rates in tuna purse-seine fisheries.
- Published
- 2016
26. Forecasted consequences of simulated FAD moratoria in the Atlantic and Indian Oceans on catches and bycatches
- Author
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Escalle, Lauriane, primary, Gaertner, Daniel, additional, Chavance, Pierre, additional, Delgado de Molina, Alicia, additional, Ariz, Javier, additional, and Mérigot, Bastien, additional
- Published
- 2016
- Full Text
- View/download PDF
27. Environmental factors and megafauna spatio-temporal co-occurrence with purse-seine fisheries
- Author
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Université de Montpellier, Escalle, Lauriane, Pennino, Maria Grazia, Gaertner, Daniel, Chavance, Pierre, Delgado de Molina, Alicia, Demarcq, Hervé, Romanov, Evgeny, Merigot, Bastien, Université de Montpellier, Escalle, Lauriane, Pennino, Maria Grazia, Gaertner, Daniel, Chavance, Pierre, Delgado de Molina, Alicia, Demarcq, Hervé, Romanov, Evgeny, and Merigot, Bastien
- Abstract
Tropical tuna purse-seine fisheries spatially co-occur with various megafauna species, such as whale sharks, dolphins and baleen whales in all oceans of the world. Here, we analyzed a 10-year (2002–2011) dataset from logbooks of European tropical tuna purse-seine vessels operating in the tropical Eastern Atlantic and Western Indian Oceans, with the aim of identifying the principle environmental variables under which such co-occurrence appear. We applied a Delta-model approach using Generalized Additive Models (GAM) and Boosted Regression Trees (BRT) models, accounting for spatial autocorrelation using a contiguity matrix based on a residuals autocovariate (RAC) approach. The variables that contributed most in the models were chlorophyll-a concentration in the Atlantic Ocean, as well as depth and monsoon in the Indian Ocean. High co-occurrence between whale sharks, baleen whales and tuna purse-seine fisheries were mostly observed in productive areas during particular seasons. In light of the lack of a full coverage scientific observer on board program, the large, long-term dataset obtained from logbooks of tuna purse-seine vessels is highly important for identifying seasonal and spatial co-occurrence between the distribution of fisheries and megafauna, and the underlying environmental variables. This study can help to design conservation management measures for megafauna species within the framework of spatial fishery management strategies.
- Published
- 2016
28. Environmental factors and megafauna spatio-temporal co-occurrence with purse-seine fisheries
- Author
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Escalle, Lauriane, primary, Pennino, Maria Grazia, additional, Gaertner, Daniel, additional, Chavance, Pierre, additional, Delgado de Molina, Alicia, additional, Demarcq, Hervé, additional, Romanov, Evgeny, additional, and Merigot, Bastien, additional
- Published
- 2016
- Full Text
- View/download PDF
29. Forecasted consequences of simulated FAD moratoria in the Atlantic and Indian Oceans on catches and bycatches.
- Author
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Escalle, Lauriane, Gaertner, Daniel, Chavance, Pierre, de Molina, Alicia Delgado, and Mérigot, Bastien
- Subjects
- *
FISHERY closures , *BYCATCHES , *FISH aggregation devices , *MONTE Carlo method - Abstract
Given the increasingly extensive use of drifting fish aggregation devices (FADs) by the purse-seine fisheries targeting tropical tunas, fishing effort restrictions have been introduced to manage tropical tuna stocks. However, these measures are focused on the protection of juvenile tunas and do not take account of the potential impact on bycatch or associated megafauna (whales and whale sharks). An iterative "fishingday" Monte Carlo simulation model was developed to investigate the consequences on tropical tunas and bycatch of introducing extensive area 6-month moratoria on FAD activities. The model allowed for variability in a range of plausible values of the parameters characterizing the fishing operations conducted by European purse-seiners in the eastern tropical Atlantic and western Indian Oceans for the period 2005-2014. Monte Carlo simulations, using probabilities based on these fishery data, were carried out for the French and Spanish fishing fleets separately to account for differences in fishing strategies. The models predicted a decrease in FAD sets and an increase in free school sets. As a consequence, the catch of small tuna (<10 kg) decreased while the catch of large tuna (≥10 kg) increased, leading to an overall increase in tuna catch of 100-200 tons/year/vessel in the Atlantic Ocean, and a decrease of 400-1500 tons/year/vessel in the Indian Ocean. The bycatch decreased in the Indian Ocean, while in the Atlantic Ocean billfishes, turtles and chondrichthyans bycatch increased slightly and other bony fishes decreased. Because fishing practices were modified, whale and whale shark associated sets increased slightly in the Indian Ocean. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
30. Mortality of marine megafauna induced by fisheries: Insights from the whale shark, the world’s largest fish
- Author
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Capietto, Anna, primary, Escalle, Lauriane, additional, Chavance, Pierre, additional, Dubroca, Laurent, additional, Delgado de Molina, Alicia, additional, Murua, Hilario, additional, Floch, Laurent, additional, Damiano, Alain, additional, Rowat, David, additional, and Merigot, Bastien, additional
- Published
- 2014
- Full Text
- View/download PDF
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